The present invention relates to an adjustable chair construction having an adjustable back, seat, and armrests configured to provide optimal postural support to a seated user during recline. More particularly, the back includes a flexible back shell and a lumbar mechanism for adjusting a shape of the flexible back shell for improved lumbar support. The chair further includes a seat, a reclineable back, and (in one version) armrests that move with a synchronous motion relative to the seat and back during recline of the back.
There are many adjustable chairs in the art, including chairs having adjustable backs and adjustable armrests. However, adjustability continues to be a concern since users have so many different body shapes and preferences. Further, improvements are desired in the adjustment mechanisms, so that they are simpler and more intuitive to operate.
In regard to synchronized seat and back movements, synchronous chairs, such as Steelcase""s Sensor chair, have gained wide market acceptance for providing postural support during back recline while also providing simultaneous seat and back rotation that minimizes sheer or xe2x80x9cshirt pullxe2x80x9d in the lumbar area of a seated user. However, further improvement is desired so that these mechanisms provide even greater adjustability in terms of the particular synchrotilt motion that they provide. For example, a non-uniform synchronous motion is often desired, where the back and seat move at a changing ratio during recline. From a manufacturing standpoint, it is preferable that these new movements and back tilt axis locations still use as many existing parts as possible, and that they be as simple as possible. Also, many consumers are looking for a new modernistic appearance.
In regard to armrests, there are many adjustable armrests on the market, some of which move with the seat during recline of the back and others of which move with the back during recline. However, no known existing chair includes adjustable armrests that move with a synchronous rotating motion during back recline that is different from both the back and the seat. Further, no known chair includes means for adjusting an armrest in a manner that causes the synchronous angular rotation of the armrest and its rotational path to change depending upon the adjustment. Also, an adjustable armrest is desired that is horizontally rotatable to different angular/lateral positions, yet that is secure and also intuitive to operate and adjust. At the same time, these motions preferably are provided by an adjustment mechanism and armrest support structure that is cost effective, readily manufacturable, and that provides a modernistic and pleasing visual appearance.
Accordingly, a chair including an improved back construction, armrest construction, and overall construction is desired solving the aforementioned problems, but that provides the adjustability, low cost, and ease of assembly needed in the competitive chair industry.
In one aspect of the present invention, a chair includes a base having a control, a seat including a seat support assembly pivotally supported by the control for movement about a seat tilt axis, and a back tilt bracket subassembly pivoted to the control for movement about a first back tilt axis. The control biases the seat support and the back tilt bracket subassembly toward upright positions. A back support structure is pivoted at a lower end to the back tilt bracket subassembly for movement about a second back tilt axis spaced from the first back tilt axis, and a backrest is supported on the back support structure.
In another aspect of the present invention, a chair includes a base having a control assembly, and a seat pivotally supported by the control assembly for movement about a seat tilt axis, the seat having a rear edge. A back support is pivoted to the control assembly for movement about a back tilt axis that is located rearward of the rear edge of the seat, the seat and back support being operably supported by the control assembly for synchronous movement. A backrest assembly is operably supported on the back support and the control assembly for optimal support to a seated user""s lumbar.
In another aspect of the present invention, a chair includes a base having a control housing and an energy mechanism positioned in the control housing, and a seat support pivotally supported by the control housing for movement about a seat tilt first axis, the seat support having a rear edge and including side supports that extend above the seat support to a location generally horizontally aligned with a hip joint of a seated user. A back tilt bracket subassembly is pivoted to the control housing for movement about a back tilt second axis. The back tilt bracket subassembly and the seat support are operably connected to the control housing for synchronous movement during recline of the back tilt bracket subassembly. The energy mechanism biases the back tilt bracket subassembly and the seat support to an upright position. A back support is pivoted to a rear end of the back tilt bracket subassembly for movement about a back tilt third axis that is located rearward of a rear edge of the seat support. A backrest frame is pivoted to an upper end of the back support at a fourth axis and pivoted to an upper end of the side supports at a fifth axis, and a backrest is operably supported on the backrest frame for flexible postural support.
In another aspect of the present invention, a back construction for a chair includes a flexible back shell having a lumbar section with side edge sections and an intermediate section horizontally between the side edge sections. A lumbar slide slidably engages a rear surface of the back shell and is operably supported thereagainst. The lumbar slide has an adjustable forwardly-convex shape optimally suited for supporting a seated user""s lumbar and is adjustable to flex the side edge sections of the lumbar section of the back shell forwardly relative to the intermediate section to provide different amounts and shapes of lumbar support to the seated user.
In another aspect of the present invention, a chair includes a back, a base including a control assembly, and a seat supported on the control assembly. A back spine assembly supports the back on the control assembly, the back spine assembly extending generally vertically and being positioned at a location generally rearward of the backrest. An armrest assembly is slidably supported on the back spine assembly for vertical height adjustment.
In yet another aspect of the present invention, a method includes providing a base, and providing a reclineable back, a seat, and an armrest each operably supported on the base. The method further includes simultaneously pivoting the seat, the armrest, and the reclineable back upon recline of the reclineable back at three different rates of rotation.
In another aspect of the present invention, a chair includes a seat, a back, and a lumbar adjustment mechanism. The lumbar adjustment mechanism includes opposing lateral support arms that are forwardly and rearwardly adjustably movable and configured to wrap partially around and adjustably support a seated user""s sides.
In another aspect of the present invention, a chair includes a back construction including a flexible polymeric sheet with a front surface configured to comfortably support a back of a seated user. The polymeric sheet is made of light-permeable material that is transparent or translucent, such that mechanisms on the back construction can be seen through the back construction from a front of the chair.
In another aspect of the present invention, chair comprises a back construction including a flexible polymeric sheet with a front surface configured to comfortably support a back of a seated user. The polymeric sheet includes a V-shaped pattern of vertical slots and a U-shaped pattern of horizontal slots around the V-shaped patterns. The U-shaped and V-shaped patterns are arranged to provide predetermined regions of non-uniform flexibility to the sheet.
In yet another aspect of the present invention, an armrest construction for a chair includes an armrest support, and an armrest member pivoted to the armrest support at a main pivot for horizontal movement between a plurality of different angled positions, the armrest member having a front end and a rear end. A latch member is pivoted to one of the armrest support and the armrest member at a latch pivot. The latch member includes a handle portion near the front end of the armrest member and further includes an interlock section spaced from the handle portion. At least one of the armrest support and the armrest member includes a plurality of features that correspond with the plurality of different angled positions. The latch member is pivotable between a release position where the interlock section is disengaged from the features so that the armrest member can be adjusted, and pivotable to an engaged position where the interlock section is positively engaged with a selected one of the features to prevent horizontal adjustment.
These and other inventive aspects, objects, and advantages will become apparent to one of ordinary skill in the art upon review of the attached specification, claims, and appended drawings.